This invention relates to diagnostic ultrasonic imaging systems, and more particularly, to diagnostic ultrasonic imaging systems displays that are optimally suited to displaying ultrasonic images.
Diagnostic ultrasonic imaging systems are commonly used to image a wide variety of organs and tissues within the human body. A typical ultrasonic imaging system 10 is shown in FIG. 1. The imaging system 10 includes an ultrasonic scanhead 14 that is adapted to be placed in contact with a portion of a body that is to be imaged. The scanhead 14 is coupled to a system chassis 16 by a cable 18. The system chassis 16, which is mounted on a cart 20, includes a keyboard 24 by which data may be entered into a processor (not shown) that is included in the system chassis 16. A display, which may be a cathode ray tube (xe2x80x9cCRTxe2x80x9d) display or a flat panel display 30 having a viewing screen 34, is placed on an upper surface of the system chassis 16. Such flat panel displays 30, such as liquid crystal displays (xe2x80x9cLCDxe2x80x9d), have been proposed for use in ultrasonic imaging system in, for example, U.S. Pat. No. 5,924,988 to Burris et al., which describes significant advantages that can be achieved by using a relatively thin and lightweight flat panel display.
The images displayed by conventional ultrasonic imaging systems have, in the past, been somewhat static. However, with the development of faster ultrasonic processors, it is possible to display real-time ultrasonic images of rapidly moving tissues and organs, such as a beating heart. However, it has been discovered that flat panel displays, such as liquid crystal displays, suggested for use in, for example, the above-cited patent to Burris et al., cannot optimally portray rapidly moving tissues and organs. This inability is due primarily to the relatively slow response times of conventional flat panel displays proposed for use in ultrasonic imaging systems. Thus, although the small size and light weight of flat panel displays proposed for use in ultrasonic imaging systems would provide many advantages, these advantages can be achieved only by sacrificing the ability to optimally display rapidly moving images.
Another problem that has been discovered with the use of flat panel displays proposed for use in ultrasonic monitoring systems is their lack of dynamic range or contrast ratio. It is often important to be able to discern subtle variations in the intensity of ultrasonic images. For example, it can be important to be able to differentiate an area reflecting substantially no ultrasonic energy, which should appear black, from an area reflecting a slight amount of ultrasonic energy, which should appear almost black. An ultrasonic image displayed on a flat panel display screen with insufficient dynamic range or contrast ratio will be unable to show the area reflecting substantially no ultrasonic energy darkly enough to differentiate that area from the area reflecting a slight amount of ultrasonic energy.
In addition to having a fast response time and a large dynamic range, a flat panel display used to view images in an ultrasonic imaging system should also have a wide viewing angle. The display of an ultrasonic imaging system is often mounted on a cart, but the sonographer or other health care practitioner is often positioned off to the side of the cart next to a patient. Unless the display for the ultrasonic imaging system can be viewed from the side, it may be difficult for the health care practitioner to view the ultrasonic image without taking his or her attention away from the patient. Furthermore, even within the viewing angle of flat panel displays proposed for use in ultrasonic imaging, the color or brightness of the image can vary substantially as the viewing angle is varied.
A need therefore exists for an ultrasonic imaging system having a display that has a response time sufficiently short to display rapidly moving images, a dynamic range or contrast ratio sufficient to discern slight variations in the intensity of ultrasonic echoes, and a view angle that is sufficiently wide that the display can be easily viewed by a health care practitioner while devoting sufficient attention to a patient being examined.
An ultrasonic imaging system includes a system chassis, an ultrasonic scanhead coupled to the system chassis, and an organic light emitting device display coupled to the system chassis. The display includes a viewing screen on which an ultrasonic image can be displayed with superior response times, contrast ratios, and viewing angles. The response time of the organic light emitting device display is preferably less than 10 ms, and more preferably less than 1 ms. The contrast ratio of the organic light emitting device display is preferably at least 1000:1, and more preferably at least 4000:1. The horizontal and vertical viewing angle of the organic light emitting device display is preferably at least 160 degrees, and more preferably at least 180 degrees.